1. Field of the Invention
This invention relates to an apparatus for shaping food products, in particular to an apparatus for cutting and shaping spherical food products, such as a bean-jam bun or bean-jam rice dumpling, from two-layered bar-shaped food material continuously extruded from an extruder.
2. Description of the Prior Art
A first conventional apparatus for cutting and shaping a bean-jam bun is disclosed, e.g., in Japanese Utility Model Publication No. 5-25432. This conventional apparatus includes at least three hexahedral plastic pieces, each hexahedral piece having two adjacent sliding side surfaces. The hexahedral pieces are combined into an assembly such that these sliding surfaces abut each other. The assembly is held in a polygonal housing so as to form a central opening surrounded by parts of the sliding surfaces, and the hexahedral pieces are made to slide on each other so as to open and close the central opening so that a dough bar passing therethrough is cut and shaped.
A problem with the first conventional apparatus disclosed in Japanese Utility Model Publication No. 5-25432 is that the plastic hexahedral pieces encased in the housing tend to expand and be clogged or burnt by heat generated during the operation, which thus must be discontinued.
A second conventional apparatus is disclosed, e.g., in Japanese Patent Publication No. 5-9051. This conventional apparatus includes identically-shaped polyhedral members which are pivoted on fulcrums equidistantly disposed on an imaginary circle surrounding a central opening. The polyhedral members are arranged such that each polyhedral member synchronously rotates on its respective fulcrum, while a tip of each polyhedral member tracks a side surface of an adjacent member, so as to open and close the central opening to cut and shape food material passing therethrough.
A problem with the second conventional apparatus disclosed in Japanese Patent Publication No. 5-9051 is that, other than at the tips of the polyhedral members, gaps are formed between the side surfaces of adjacent polyhedral members while the tips track the side surfaces of adjacent polyhedral members. This allows food material to enter the gaps so that the surfaces of the food material may be disfigured.
Another problem with the second conventional apparatus is that since only the tip portions of the polyhedral members touch the side surfaces of adjacent members, the tip portions eventually wear away so that the central opening cannot be completely closed. Therefore, the effects of cutting and shaping a spherical body are reduced.